Field of the Invention
The invention relates to the fingerprint identification technology, and more particularly to a fingerprint detection apparatus disposed under a protective glass, and a manufacturing method thereof, wherein the fingerprint detection apparatus is disposed under a protective glass by a distance and still can capture a fingerprint pattern.
Description of the Related Art
FIG. 1 shows a structure of a fingerprint input device disclosed in U.S. Pat. No. 6,829,375. Referring to FIG. 1, the conventional fingerprint input device comprises a two-dimensional image sensor 101, a light source 102 and a thinned protective glass 103. The user's finger directly contacts the thinned protective glass 103. The light source 102 emits the light with the designated frequency to the finger, and the finger reflects the scattered light. The two-dimensional image sensor 101 receives the scattered light directly from the finger's ridge portion, and the scattered light scattered by the finger's valley portion diffuses.
In the prior art, the protective glass is very thin, and the image sensor detects the ridge portion as the bright portion and detects the finger's valley portion as the dark portion.
However, when the protective glass is too thick or an air gap is formed between the image sensor and the protective glass, the image sensor cannot capture the fingerprint.